Dembele's discipline has been in the spotlight since arriving from Borussia Dortmund in 2017 but the Barcelona forward dazzled with a stunning goal in the 1-1 draw with Tottenham.
The 21 year-old France international opened the scoring in the seventh minute when he robbed and stormed past Kyle Walker-Peters on the halfway line before evading Harry Winks and slotting past Hugo Lloris.
Valverde was pleased with Dembele post-match, telling reporters: "He has made a great goal, within reach of players with his talent.
"We are happy with him and we said that throughout the season things happen that we try to solve internally, we hope that he and the rest will continue to give us many joys."
Dembele reportedly arrived two hours late for training session and when asked if all was forgiven, Valverde replied: "I do not know, tomorrow [Wednesday] we have training."
Already assured of a last-16 spot, Barca was forced to share the spoils in Group B after Lucas Moura equalised with five minutes remaining at Camp Nou.
While Barca was unable to secure maximum points, the LaLiga giant equalled Bayern Munich's record of 29 consecutive home games without defeat in the Champions League – a run dating back to September 2013.
"We controlled the game well in the first half, Dembele's goal reassured us and then we had little trouble," Valverde said.
"In the second half we imagined that they would get on top of us because they were forced to do so and we lacked calm to have the ball and take the game from the defence.
"Maybe we were not as well as we would like to make longer possessions but you have to understand the situation, we did not play for anything and they risked all."
Lionel Messi was named among the substitutes for the sixth and final Group B fixture, though the Barca superstar came off the bench just past the hour-mark.
"It's better for him to play for a while and to be in motion, he likes it," Valverde said. "We also and I don't have to tell you about the fans, there have been players who were not there because we had an intense match three days ago.
"We wanted to see players like [Carles] Alena or [Juan] Miranda in difficult situations, as well as the response of [Jasper] Cillessen, [Thomas] Vermaelen, Arthur or Munir, we did not want to lose competitive level against a very strong team."